Load-lock technique

ABSTRACT

Disclosed is a load-lock system and an exposure apparatus having the same, wherein the load-lock system includes a chamber, an exhaust system for exhausting a gas from the inside of the chamber, a heater, a first valve for opening/closing an opening of the chamber, a supply system for supplying a gas into the chamber through the heater and the first valve, and a second valve for opening/closing an opening of the chamber provided for conveyance of an object, wherein the supply system supplies a the gas before the object is conveyed into the chamber and when the second valve is held opened, and wherein the exhaust system exhausts a gas supplied from the supply system, after the conveyance of the object.

FIELD OF THE INVENTION AND RELATED ART

This invention relates to load-lock technique applicable to productionof various microdevices such as, for example, semiconductor chips (e.g.,IC or LSI), display devices (e.g., liquid crystal panel), detectingelements (e.g., magnetic head), and image pickup devices (e.g. CCD).

The density and speed of a semiconductor integrated circuit have beenimproved significantly and, with this trend, the linewidth of anintegrated circuit pattern has been narrowed more and more. This forcesfurther improvements in the semiconductor manufacturing method. Asregards exposure apparatuses used for forming a resist pattern in alithographic process which is one of semiconductor manufacturingprocesses, those using vacuum ultraviolet light (VUV light) such as KrFlaser light (wavelength 248 nm), ArF laser light (wavelength 193 nm) orF2 laser light (wavelength 157 nm) have been developed. Currently, EUVexposure apparatuses that use extreme ultraviolet light (EUV light) of awavelength of about 10 nm, are being developed. Exposure apparatusesusing electron beam are being developed on the other hand.

If the wavelength is short such as EUV light, X-rays or electron beam,the exposure light is attenuated in the atmosphere. In consideration ofthis, to avoid attenuation of exposure light, the exposure process iscarried out in a vacuum ambience or a reduced pressure He ambience.

In process machines such as sputtering apparatus, carrying out a processin a vacuum ambience is common. Loading and unloading a substrate to beprocessed, from the atmosphere into a process chamber (vacuum ambience),is carried out by way of a load-lock chamber (housing).

In exposure apparatuses as well, load-lock chambers are used when asubstrate to be exposed is loaded into a vacuum ambience (exposureambience).

Referring now to FIG. 5, the structure of a known type load-lock systemwill be explained. Load-lock chamber (housing) 101 is provided at a sideof a main chamber 102 in which an exposure process is to be carried out.There is an atmosphere side gate valve 104 at one side of the load-lockchamber 101, and a vacuum side gate valve 103 at the other side of theload-lock chamber. For evacuation to create a vacuum level in thechamber, there are an exhaust pipe 105, an exhaust valve 106 and avacuum pump 107. Furthermore, for resuming an atmospheric pressureinside the chamber from the vacuum level, there are a gas supplying pipe108 and a gas supplying valve 109.

For loading a substrate 110 into the main chamber 102 which is in vacuumstate, the vacuum side gate valve 103, the exhaust valve 106 and the gassupply valve 109 are kept closed and, on the other hand, the atmosphereside gate valve 104 is opened. Then the substrate 110 is introduced intothe load-lock chamber 101. Subsequently, the atmosphere side gate valve104 is closed, and the exhaust valve 106 is opened. Normally, the vacuumpump 107 is kept driven uninterruptedly. As regards the exhaust valve106, generally, a butterfly valve is used. By opening the exhaust valve106, the atmospheric gas inside the load-lock chamber 101 is dischargedoutwardly. After the exhausting is completed, the exhaust valve 106 isclosed and the vacuum side gate valve 103 is opened, and the substrateis introduced into the main chamber 102. After the substrate is loaded,the vacuum side gate valve 103 is closed.

For unloading a processed substrate out of the main chamber 102, theload-loch chamber is exhausted and placed in vacuum state (all thevalves and gate valves are kept closed), and thereafter the vacuum sidegate valve 103 is opened. Then, the substrate 110 is unloaded and movedback into the load-lock chamber 110. After this, the vacuum side gatevalve 103 is closed and, subsequently, the gas supply valve 109 isopened. The gas supply pipe 108 is communicated with the atmosphere,such that, by opening the gas supply valve 109, the inside of theload-lock chamber 101 can be filled with atmosphere. After anatmospheric pressure is reached, the atmosphere side gate valve 104 isopened, and the substrate 110 is moved outwardly.

With the procedure described above, it is assured that a substrate 110is conveyed between the atmosphere and the main chamber 102 withoutdamaging the vacuum state inside the main chamber 102.

Japanese Laid-Open Patent Application, Publication No. 2001-102281discloses an example of load-lock chamber that can be applied to asemiconductor exposure apparatus or the like.

However, in the load-lock chamber structure such as described above,when the gas is exhausted to create a vacuum level in place of theatmospheric pressure state, at the moment as the exhaust valve is openedthe atmospheric air inside the chamber is exhausted rapidly. This causesadiabatic expansion of the air and, thus, the temperature decreasessuddenly. As a result of this, the moisture content contained in theatmosphere is frozen and adhered to the substrate surface, causingcontamination of it. Simultaneously, since heat is carried away from thesubstrate, the temperature of the substrate is lowered. If the load-lockoperation and operations following it are carried out while thesubstrate temperature is low, the substrate temperature gradually risesin accordance with the surrounding temperature. Such temperature rise isa serious factor for slowing down the production yield, particularly ina process (such as lithographic process) where precise temperaturecontrol is required.

Generally, the inconveniences described above can be avoided by carryingout the vacuum exhausting slowly to provide a sufficient time fortransmission of heat between the air and the surrounding ambience.Load-lock systems are incorporated into process machines such as filmforming apparatus and, in such machines, the time required for theprocess itself is relatively long. Thus, there is a margin with respectto time that can be spent on substrate loading and unloading byload-locking. Even if the vacuum exhausting takes time, it does notaffect the throughput of the apparatus.

Among exposure apparatuses, those that are arranged to carry out theexposure process in a vacuum have already been used in practice such aselectron beam direct drawing apparatus, for example. Such apparatus havea very low throughput by nature, and the time necessary for loading andunloading a substrate by load-locking does not raise a problem. However,EUV exposure apparatuses and the like are machines designed for massproduction of MPUs or memories, for example, and a very high throughputof an order of 100 pieces per hour is required. If the load-lockstructure is arranged for slow exhausting, although the inconveniencessuch as substrate contamination or temperature decrease could be avoidedthereby, it needs a very long time for substrate loading and unloading.This is a serious factor for throughput decrease of the apparatus.Practically, therefore, the load-lock structure such as described abovecan not be applied to a machine such as EUV exposure apparatus in whicha large throughput is required.

SUMMARY OF THE INVENTION

It is accordingly an object of the present invention to provideload-lock technique by which high-speed vacuum exhausting is enabledwhile reducing or suppressing contamination or temperature decrease ofan object to be loaded and/or unloaded.

In accordance with an aspect of the present invention, there is provideda load-lock system, comprising: a chamber; an exhaust system forexhausting a gas from the inside of said chamber; a heater; a firstvalve for opening/closing an opening of said chamber; a supply systemfor supplying a gas into said chamber through said heater and said firstvalve; and a second valve for opening/closing an opening of said chamberprovided for conveyance of an object: wherein said supply systemsupplies a the gas before the object is conveyed into said chamber andwhen said second valve is held opened, and wherein said exhaust systemexhausts a gas supplied from said supply system, after the conveyance ofthe object.

In accordance with another aspect of the present invention, there isprovided a load-lock method, comprising: a first step for supply a gasinto a chamber through a heater and a first valve which opens/closes anopening formed in the chamber; a second step for closing the first valveafter said first step; a third step for conveying an object into thechamber through a second valve that opens/closes an opening formed inthe chamber; a fourth step for closing the second valve after said thirdstep; and a fifth step for exhausting a gas inside the chamber, aftersaid second step and also after said fourth step.

Briefly, in accordance with the present invention, load-lock techniqueby which high-speed vacuum exhausting is enabled while reducing orsuppressing contamination or temperature decrease of an object to beloaded and/or unloaded, can be provided.

These and other objects, features and advantages of the presentinvention will become more apparent upon a consideration of thefollowing description of the preferred embodiments of the presentinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view for explaining a load-lock system accordingto a first embodiment of the present invention.

FIG. 2A is a schematic view for explaining a state in which a heated gasis blown, in the first embodiment of the present invention.

FIG. 2B is a schematic view for explaining a state in which a substrateis placed inside the load-look chamber, in the first embodiment of thepresent invention.

FIG. 2C is a schematic view for explaining a state in which a vacuumside gate valve is opened, in the first embodiment of the presentinvention.

FIG. 2D is a schematic view for explaining a state in which conveyanceof the substrate has been completed, in the first embodiment of thepresent invention.

FIG. 3 is a schematic view for explaining a load-lock system accordingto a second embodiment of the present invention. FIG. 2A is a schematicview for explaining a state in which a heated gas is blown, in the firstembodiment of the present invention.

FIG. 4A is a schematic view for explaining a state in which a heated gasis blown, in the second embodiment of the present invention.

FIG. 4B is a schematic view for explaining a state in which a substrateis being loaded, in the second embodiment of the present invention.

FIG. 4C is a schematic view for explaining a state in which vacuumevacuation is being carried out, in the second embodiment of the presentinvention.

FIG. 4D is a schematic view for explaining a state in which thesubstrate is being loaded into the main chamber, in the secondembodiment of the present invention.

FIG. 5 is a schematic view of a known type load-lock system.

FIG. 6 is a schematic view, showing an example of exposure apparatus.

FIG. 7 is a flow chart for explaining the procedure of devicemanufacturing processes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be describedwith reference to the attached drawings and in relation to exampleswherein the present invention is applied to an exposure apparatus.

Embodiment 1

FIG. 1 illustrates a load-lock system according to a first embodiment ofthe present invention. The first embodiment is applied to an EUV(extreme ultraviolet) exposure apparatus wherein exposure is carried outin a vacuum ambience. Denoted at 1 is the load-lock system of thepresent invention, and denoted at 2 is a main chamber which is used asan exposure chamber of the exposure apparatus. The main chamber isfilled with a vacuum ambience or a particular ambience such as reducedpressure He, for example. The load-lock chamber 1 serves to enableloading a substrate 10 thereinto from the atmosphere without breakingthe vacuum ambience or particular ambience, and also to assure unloadingthe substrate 10, after being processed inside the main chamber 2,outwardly.

Basically, the present invention is directed to a load-lock system, andit is not always necessary that the machine placed at the main chamberside of the load-lock system is an exposure apparatus. It may be anetching apparatus, for example. The structure of the load-lock system 1will be described below in greater detail.

Denoted at 16 is a load-lock chamber (housing) which is a majorcomponent of the load-lock system 1, and it is a vacuum chamber. Denotedat 3 is a vacuum side gate valve that functions as an interface betweenthe main chamber 2 and the load-lock chamber 16. As this gate valve 3 isopen, an opening defined in the side wall of the load-lock chamber 16through which a substrate can be conveyed. As the gate valve 3 isclosed, the chamber can be gas-tightly closed. Denoted at 4 is anatmosphere side gate valve, and it serves to define an opening forconveyance of a substrate 10 between the load-lock chamber 16 and theatmosphere (or an ambience different from that of the exposureapparatus). When the gate valve 4 is open, an opening is defined in theside wall of the load-lock chamber 16 through which the substrate 10 canbe conveyed. When it is closed, on the other hand, the load-locking wallsurface is gas-tightly closed to prevent the atmosphere from enteringinto the load-lock chamber 16.

Denoted at 5 is an exhaust pipe which is connected to a vacuum pump 7through an exhaust valve 6. Normally, the vacuum pump 7 is held indriven state. As the exhaust valve 6 is opened, the inside of theload-look chamber 16 is communicated with the vacuum pump 7, whereby thegas inside the load-lock chamber 16 is exhausted outwardly. Denoted at 8is a gas supply pipe for supplying a gas into the load-lock chamber 16.There is a gas supply valve 9 for supplying a gas and for stopping thegas supply. In this example, the tip end of the pipe 8 is open to theatmosphere, and the gas supplied into the load-lock chamber 16 is anair. However, the pipe 8 may be connected to a gas supply line so thatany desired gases appropriate to the working condition, such as dry airor dry nitrogen, for example, may be used. The pipe 8 serves to supply agas (pressure) into the load-lock chamber 16 to turns the insidepressure back to the atmospheric pressure to thereby allow opening ofthe atmosphere side gate valve 4.

Denoted at 11 is a substrate table mounted inside the load-lock chamber,and this is a table on which a substrate 10 is loaded, inside theload-lock chamber 16. The substrate table 11 has three pins. Since thecontact to the substrate 10 is limited to these three points,contamination of the substrate due to adhesion of particles can besuppressed to a lowest level. Denoted at 12 is a hot or heated gasintake valve which is provided at the ceiling of the load-lock chamber16. It functions to define an opening for supplying a heated atmosphereinto the load-lock chamber 16. When the heated gas supply is to bestopped, the intake valve 12 is closed, and the chamber is gas-tightlyclosed. As will be described later, the opening of the intake valve 12should be wide enough to prevent that it interferes with the flow of gasgenerated by a fan 14. To this end, the intake valve 12 should desirablyhave a similar structure as of the gate valve used for loading/unloadingthe substrate 10. However, a butterfly valve may be used therefor.Disposed above the intake valve 12 is a filter 13. Above the filter 13,there are a fan 14 and a heater 15. The top of the heater 15 is open tothe atmosphere. Thus, an atmospheric air is introduced from the outsidein response to the operation of the fan 14, and it is heated by theheater 15. The heated air flows through the filter 13, and it flows intothe load-lock chamber 16. The filter 13 is provided to prevent anyparticles from entering into the load-lock chamber 16.

The operation of the load-lock system will now explained below, insequence.

FIG. 2A illustrates a state in which the atmosphere side gate valve ofthe load-lock system is open. In this state, the load-lock system standsby to loading of the substrate from the atmosphere side. Here, theheated gas intake valve 12 is held opened, and the fan 14 is beingdriven. The heater 15 is being energized, such that an atmospheric airheated to a high temperature by the heater 15 is flowing into theload-lock chamber 16 from the ceiling of the load-lock chamber 16. Theheated atmospheric air flows outwardly through the opening of theatmosphere side gate valve 4. Just before the substrate 10 is introducedinto the load-lock chamber 16, the fan 14 and the heater 15 are stoppedand the heated gas intake valve 12 is closed as well. By means of aconveyance robot (not shown) disposed in the atmosphere, the substrate10 is loaded into the load-lock chamber 16 and is placed on thesubstrate table 11. FIG. 2B illustrates this stage.

After this, the atmosphere side gate valve 4 is closed and,subsequently, the exhaust valve 6 is opened, whereby the inside of theload-lock chamber 16 is evacuated.

Generally, if evacuation is carried out rapidly from the state of normaltemperature and atmospheric pressure, due to adiabatic expansion of theair, the moisture content contained in the air is frozen and falls aswater drops onto the substrate, causing contamination of the substrate.Furthermore, heat is carried away from the substrate to causetemperature decease and, thus, contraction of the substrate. Thisadversely affects the registration precision in the exposure apparatus(exposure chamber 2), or it necessitates time-consuming temperatureadjustment of the substrate in the exposure apparatus. In considerationof this, in conventional load-lock systems, the opening degree of theexhaust valve has to be controlled to perform the vacuum exhaustingslowly. In the load-lock system 1 of this embodiment, as comparedtherewith, there is no such necessity and the exhausting can be done athigh speed. This is because, by supplying airs heated to hightemperature from the outside when the load-lock chamber 16 is open tothe atmosphere, the gas (air) originally contained inside the chamber isreplaced by the high-temperature gas and because the temperature of thechamber inner wall is raised by the heated air, such that, even by rapidvacuum evacuation, the gas temperature does not decrease to thetemperature that causes freeze of moisture content. If desired, the fan14, the heater 15 and/or the heated gas intake valve 12, for example,may be controlled so that the substrate temperature is maintained at atemperature suited for the process to be carried out inside the exposureapparatus (exposure chamber 2).

By monitoring the vacuum level by use of a vacuum gauge disposed insidethe load-lock chamber 16, whether vacuum evacuation has been completedor not is checked. If a predetermined vacuum level is reached, theexhaust valve 6 is closed and vacuum evacuation is discontinued. Afterthis, the vacuum side gate valve 13 is opened, such that as shown inFIG. 2C the main chamber 2 and the load-lock chamber 15 are communicatedwith each other. There is a conveyance robot (not shown) provided insidethe main chamber 2, that operates to convey the substrate 10 into themain chamber. After this, the vacuum side gate valve 3 is closed asshown in FIG. 2D.

With the procedure described above, the sequence for loading thesubstrate 10 into the main chamber 2 from the atmosphere side iscompleted.

The sequence for unloading the substrate 10 from the main chamber 2 maybe essentially the same that in conventional load-lock systems, anddescription thereof will be omitted here.

Embodiment 2

FIG. 3 illustrates a load-lock system according to a second embodimentof the present invention. The second embodiment is applied to anexposure apparatus such as EUV (extreme ultraviolet) exposure apparatuswherein exposure is carried out in a vacuum ambience or a particularambience such as reduced pressure He. FIG. 3 is a plan view of theexposure apparatus, as seen from the above. Structural components havingsimilar functions as those of the first embodiment are denoted bycorresponding reference numerals. Denoted in the drawing at 1 is theload-lock system, and denoted at 2 is a main chamber that defines aplace where the exposure process is to be carried out.

Denoted at 16 is a load-lock chamber which is a major component of theload-lock system 1. Denoted at 3 is a vacuum side gate valve, anddenoted at 4 is an atmosphere side gate valve. These valves function todefine an opening for passage of a substrate 10 between the load-lockchamber 16 and the main chamber 2 or between the atmosphere and theload-lock chamber 12, or to gas-tightly close the chamber.

Denoted at 5 is an exhaust pipe, and denoted at 7 is a vacuum pump 7,for exhausting the load-lock chamber 16. Denoted at 8 is a gas supplypipe, and denoted at 9 is a gas supply valve. The pipe 8 and the valve 9serve to turn the inside pressure of the load-lock chamber 16 back tothe atmospheric pressure, from the vacuum level. The supplied gassupplied is an air. However, the gas supplying pipe 8 may be connectedto a gas supply line so that dry air or dry nitrogen, for example, maybe supplied.

Denoted in the drawing at 10 is a substrate which is a subject to beconveyed into the main chamber 12 and to be exposed there. Denoted at 17are pins provided at three locations in the load-lock system 1, and asubstrate is placed on these pins. Such pin structure is used todecrease the contact area with the substrate to thereby reduce adhesionof particles to the bottom face of the substrate. Denoted at 20 is a hotair generator which operates to intake an outside gas (air) and to blowit outwardly after heating the same. As will be described later, thishot air generator serves to blow an air heated to high temperaturetoward the load-lock system 1. Inside the generator 20, there are a fan14, a heater 15 and a filter 13. By rotation of the fan 14, a flow ofairs is generated, and the airs are then heated by the heater to a hightemperature. The heated air flows through the filter 13, and then theair is discharged outwardly from a blower outlet port of the generator20. The blower outlet port of the generator 20 is set at such angle thatthe heated air can be blown into the load-lock chamber 16.

Denoted at 21 is a conveyance robot in the atmosphere, and it functionsto convey a substrate to the load-lock system from outside theapparatus.

The operation of the load-lock system of this embodiment will beexplained in sequence.

The sequence for loading a substrate into the main chamber 2 is asfollows.

Here, it is assumed that FIG. 3 shows the initial state. While theinside of the load-lock chamber 16 is kept at the atmospheric pressure,the atmosphere side gate valve 4 is opened. At the same time as the gatevalve 4 is opened, the hot air generator 20 is energized to generate andblow a hot air toward the load-lock chamber 16. FIG. 4A shows thisstate.

The hot air generated from the generator 20 flows into the load-lockchamber 16 through the opening of the atmosphere side gate valve 4.Then, after being turned back inside the chamber, it flows outwardly ofthe chamber. Arrows in FIG. 4A illustrate the flow of heated air. Thehot air pushes the air originally contained in the chamber 16, such thatthe inside of the chamber is replaced by a high-temperature air. The hotair generator 20 includes a filter 13 as described above and, therefore,the amount of particles entering into the chamber is low.

Simultaneously, the substrate 10 is picked up from a substrate cassetteor the like by means of the conveyance robot 21, and it is conveyed tothe load-lock chamber 16. Just before the substrate 10 is loaded intothe load-lock chamber 16 (before it moves across the flow of hot air),the operation of the hot air generator 20 is interrupted to stop theflow of hot air. Subsequently, the conveyance robot 21 places thesubstrate 10 on the pins 17 inside the load-lock chamber 6 (FIG. 4B).Then, the hand of the conveyance robot 21 is retracted and, thereafter,the atmosphere side gate valve 4 is closed.

After the gate valve 4 is closed, the exhaust valve 6 is opened, andairs inside the load-lock chamber 16 are exhausted (FIG. 4C).

Generally, if vacuum evacuation is carried out rapidly from the state ofnormal temperature and atmospheric pressure, due to adiabatic expansionof the air, the moisture content contained in the air is frozen andfalls as water drops onto the substrate, causing contamination of thesubstrate. Furthermore, heat is carried away from the substrate to causetemperature decease and, thus, contraction of the substrate. Thisadversely affects the registration precision in the exposure apparatus(exposure chamber 2), or it necessitates time-consuming temperatureadjustment of the substrate in the exposure apparatus. In considerationof this, in conventional load-lock systems, the opening degree of theexhaust valve has to be controlled to perform the vacuum exhaustingslowly. In the load-lock system 1 of this embodiment, as comparedtherewith, there is no such necessity and the exhausting can be done athigh speed. This is because, by means of the hot air generator 20, airsheated to a high temperature are supplied continuously while theload-lock chamber 16 is kept opened to the atmosphere, the gas (air)originally contained inside the chamber is replaced by thehigh-temperature gas and because the temperature of the chamber innerwall is raised by the heated air, such that, even by rapid vacuumevacuation, the gas temperature does not decrease to the temperaturethat causes freeze of moisture content and, additionally, a decrease ofthe substrate temperature is suppressed. If desired, the fan 14 and/orthe heater 15, for example, may be controlled so that the substratetemperature is maintained at a temperature suited for the process to becarried out inside the exposure apparatus (exposure chamber 2).

By monitoring the vacuum level by use of a vacuum gauge disposed insidethe load-lock chamber 16, whether vacuum evacuation has been completedor not is checked. If a predetermined vacuum level is reached, theexhaust valve 6 is closed and vacuum evacuation is discontinued. Afterthis, the vacuum side gate valve 13 is opened, such that the mainchamber 2 and the load-lock chamber 16 are communicated with each other.There is a conveyance robot (not shown) provided inside the main chamber2, that operates to convey the substrate 10 into the main chamber (FIG.4D).

After this, the vacuum side gate valve 3 is closed.

With the procedure described above, the sequence for loading thesubstrate 10 into the main chamber 2 from the atmosphere side iscompleted.

The sequence for unloading the substrate 10 from the main chamber 2 maybe essentially the same that in conventional load-lock systems.

As described, in accordance with the structure of this embodiment, a hotair generator 20 is added outside the load-lock system, by whichload-lock technique that enables high-speed exhausting while reducingmoisture content freezing and substrate temperature decrease isaccomplished.

FIG. 6 shows an exposure apparatus for device manufacture, to which aload-lock system substrate as described hereinbefore can be applied.

This exposure apparatus is to be used for manufacture of microdeviceshaving a fine pattern formed thereon, such as semiconductor devices(semiconductor integrated circuits, for example), micromachines, orthin-film magnetic heads, for example. In this exposure apparatus,exposure light (which may include visible light, ultraviolet light, EUVlight, X-ray, electron beam, and charged particle beam, for example) asan exposure energy supplied from a light source 161 illuminates areticle R (original), and light from the reticle R is projected onto asemiconductor wafer W (substrate) through a projection system having aprojection lens 162 (which may include refractive lens, reflective lens,catadioptric lens system, and charged particle lens, for example),whereby a desired pattern is produced on the substrate.

The exposure apparatus includes a base table 151 having a guide 152 anda linear motor stator 121 fixed thereto. The linear motor stator 121 hasa multiple-phase electromagnetic coil, while a linear motor movableelement 111 includes a permanent magnet group. The linear motor movableportion 111 is connected as a movable portion 153 to a movable guide 154(stage), and through the drive of the linear motor M1, the movable guide154 can be moved in a direction of a normal to the sheet of the drawing.The movable portion 153 is supported by a static bearing 155, taking theupper surface of the base table 151 as a reference, and also by a staticbearing 156, taking the side surface of the guide 152 as a reference.

A movable stage 157 which is a stage member disposed to straddle themovable guide 154 is supported by a static bearing 158. This movablestage 157 is driven by a similar linear motor M2, so that the movablestage 157 moves leftwardly and rightwardly as viewed in the drawing,while taking the movable guide 154 as a reference. The motion of themovable stage 157 is measured by means of an interferometer 160 and amirror 159 which is fixed to the movable stage 159.

A wafer (substrate) W is held on a chuck which is mounted on the movablestage 157, and a pattern of the reticle R is transferred in a reducedscale onto different regions on the wafer W by means of the light source161 and the projection optical system 162, in accordance with astep-and-repeat method or a step-and-scan method.

It should be noted that the load-lock system of the present inventioncan be similarly applied also to an exposure apparatus in which, withoutusing a mask, a circuit pattern is directly drawn on a semiconductorwafer to expose a resist thereon.

Third Embodiment

Next, an embodiment of a device manufacturing method which uses anexposure apparatus described above, will be explained.

FIG. 7 is a flow chart for explaining the overall procedure forsemiconductor manufacture. Step 1 is a design process for designing acircuit of a semiconductor device. Step 2 is a process for making a maskon the basis of the circuit pattern design. Step 3 is a process forpreparing a wafer by using a material such as silicon. Step 4 is a waferprocess which is called a pre-process wherein, by using the thusprepared mask and wafer, a circuit is formed on the wafer in practice,in accordance with lithography. Step 5 subsequent to this is anassembling step which is called a post-process wherein the wafer havingbeen processed at step 4 is formed into semiconductor chips. This stepincludes an assembling (dicing and bonding) process and a packaging(chip sealing) process. Step 6 is an inspection step wherein anoperation check, a durability check an so on, for the semiconductordevices produced by step 5, are carried out. With these processes,semiconductor devices are produced, and they are shipped (step 7).

More specifically, the wafer process at step 4 described above includes:(1) an oxidation process for oxidizing the surface of a wafer; (ii) aCVD process for forming an insulating film on the wafer surface; (iii)an electrode forming process for forming electrodes upon the wafer byvapor deposition: (iv) an ion implanting process for implanting ions tothe wafer; (v) a resist process for applying a resist (photosensitivematerial) to the wafer; (vi) an exposure process for printing, byexposure, the circuit pattern of the mask on the wafer through theexposure apparatus described above; (vii) a developing process fordeveloping the exposed wafer; (viii) an etching process for removingportions other than the developed resist image; and (ix) a resistseparation process for separating the resist material remaining on thewafer after being subjected to the etching process. By repeating theseprocesses, circuit patterns are superposedly formed on the wafer.

While the invention has been described with reference to the structuresdisclosed herein, it is not confined to the details set forth and thisapplication is intended to cover such modifications or changes as maycome within the purposes of the improvements or the scope of thefollowing claims.

This application claims priority from Japanese Patent Application No.2003-393670 filed Nov. 25, 2003, for which is hereby incorporated byreference.

1. A load-lock system, comprising: a chamber; an exhaust system forexhausting a gas from the inside of said chamber; a heater; a firstvalve for opening/closing an opening of said chamber; a supply systemfor supplying a gas into said chamber through said heater and said firstvalve; and a second valve for opening/closing an opening of said chamberprovided for conveyance of an object; wherein said supply systemsupplies a the gas before the object is conveyed into said chamber andwhen said second valve is held opened, and wherein said exhaust systemexhausts a gas supplied from said supply system, after the conveyance ofthe object.
 2. A load-lock system according to claim 1, wherein saidfirst valve is provided at a top of said chamber.
 3. A load-lock systemaccording to claim 1, wherein said supply system stops the gas supplyprior to the conveyance of the object into said chamber.
 4. A load-locksystem according to claim 1, wherein one and the same valve is providedto function as said first and second valves.
 5. A load-lock systemaccording to claim 1, further comprising a filter, wherein said supplysystem supplies the gas into said chamber through said filter.
 6. Adevice manufacturing apparatus including a load-lock system as recitedin claim
 1. 7. A device manufacturing method including a process thatuses a device manufacturing apparatus as recited in claim
 6. 8. Anexposure apparatus including a load-lock system as recited in claim 1.9. A device manufacturing method, comprising the steps of: transferringa pattern to a substrate by use of an exposure apparatus as recited inclaim 8; and developing the substrate having the pattern transferredthereto.
 10. A load-lock method, comprising: a first step for supply agas into a chamber through a heater and a first valve which opens/closesan opening formed in the chamber; a second step for closing the firstvalve after said first step; a third step for conveying an object intothe chamber through a second valve that opens/closes an opening formedin the chamber; a fourth step for closing the second valve after saidthird step; and a fifth step for exhausting a gas inside the chamber,after said second step and also after said fourth step.
 11. A methodaccording to claim 10, wherein said first step is carried out when thesecond valve is held opened.
 12. A method according to claim 10, whereinone and the same valve is used as the first and second valves, andwherein said second and fourth steps comprise the same process to becarried out after said first step and also after said third step.
 13. Amethod according to claim 10, wherein said first step is completedbefore, in said third step, the object is conveyed into the chamber. 14.A method according to claim 10, wherein the gas is supplied into thechamber through a filter.